1. Field of the Invention
The present invention relates to transferring fluid samples and, more particularly, to a reagent transfer device for transferring a large number of fluid samples onto a very small surface area.
2. Description of the Related Art
Automated systems are used to transfer fluid samples from repositories, such as test tubes, vials or wells, to receptacles or surfaces. One such automated system is disclosed in U.S. Pat. No. 5,055,263, issued to Meltzer, entitled "Automated Pipetting System." This reference discloses a system wherein a plurality of hollow probes are used to transfer a plurality of fluid samples. A probe is dipped into the fluid repository and a volume of fluid is drawn into the probe using aspiration. The probe is retracted from the repository and repositioned above the receptacle or surface that will receive the fluid sample. The probe is lowered towards the surface and pressure is exerted against the fluid to force the fluid sample out of the probe. A plurality of probes are mounted on a carriage that is in turn mounted to an overhead frame assembly which moves the carriage independently in the X-direction and Y-direction. The carriage includes a drive mechanism that moves each probe independently in the Z-direction.
The system described above is effective for transferring fluid samples from test tubes and vials. However, the use of hollow probes to transfer fluid samples from a plurality of repositories does not provide the precision necessary to transfer a plurality of fluid samples that are in the range of about 100 microns in diameter and spaced apart by a distance of less than about 500 microns.